METHOD FOR MIRROR-LIKE POLISHING SILICON SINGLE CRYSTAL WAFER

摘要

PURPOSE:To provide a method for mirror-like polishing a silicon single crystal wafer having high flatness and completely free from work strain layer by a chemical etching means. CONSTITUTION:A method for mirror-like polishing the surface of a silicon wafer by etching comprises immersing a cut silicon wafer 1 and anodes consisting of linearly stretched out platinum wires or platinum-plated metal wires 16 in a mixture of dilute sulfuric acid and hydrofluoric acid, substantially in parallel in a mutually extremely approached state, subjecting the anodes to electrolytic reaction with a high electric current density of =0.5A/cm2 on the surfaces of the anodes to generate ozone at places near the anodes, oxidizing the surface of the silicon wafer with highly active oxygen produced by the decomposition of the ozone, and subsequently reacting, the produced silicon dioxide with the hydrofluoric acid to remove the silicon dioxide as hydrogen silicon-fluoride.